Fluoride is unable to reduce dental erosion from soft drinks

Evaluation of Struthio camelus eggshell as an in vitro alternative to extracted human teeth in preliminary screening studies on dental erosion

OBJECTIVES

This in vitro work investigates the potential of ostrich eggshell as a substitute for extracted human teeth in preliminary screening studies on dental erosion. Additionally, it aims to demonstrate the potential of ostrich eggshell compared to human enamel in evaluating the efficacy of a preventive agent in protecting against dental erosion, using an artificial mouth model.

METHODS

The experiment utilized 96 erosion testing specimens from each substrate, human enamel, and ostrich eggshell. The specimens were subjected to six different experimental regimens of increasing erosive challenge, simulating the consumption of an acidic drink. The acidic drink was delivered at a consistent volume and duration range. Both artificially stimulated and unstimulated saliva flowed throughout the experimental regimens. Surface hardness was measured using a Through-Indenter Viewing hardness tester with a Vickers diamond, while surface profiling was done using a surface contacting profilometer with a diamond stylus. An automated chemistry analyzer system was used to detect calcium and phosphate ions.

RESULTS

The study found that ostrich eggshell specimens demonstrated predictable surface loss, hardness drop, and ion loss due to the acidic challenge. Meanwhile, enamel appeared to fall short in terms of surface hardness predictability. The transient hardness loss phase, which manifests as an overlooked decrease in surface hardness despite significant ion and structural loss, may explain this phenomenon.

CONCLUSIONS

The experiment showed that assessing surface loss is essential in addition to hardness testing, particularly as certain experimental conditions may produce a false perception of tissue recovery despite the actual surface loss. By analyzing the response of ostrich eggshell specimens to erosive challenges, researchers were able to identify an "overlooked" reduction in hardness in enamel specimens. The differences in the structure, chemical composition, and biological response to erosion in the presence of artificial saliva between enamel and ostrich eggshell could explain their distinct behaviors.

Erosive potential of ice tea beverages and kombuchas

OBJECTIVES

Kombuchas and other tea-based beverages are often perceived as healthy products despite the lack of knowledge on their effects on oral health. This in vitro study determined the erosive potential of commercial kombuchas, and ice teas compared to cola drinks.

MATERIALS AND METHODS

The pH and fluoride content of 7 kombuchas and 18 tea drinks were measured with ion-selective electrodes. Calcium dissolution from hydroxyapatite grains was quantified by atomic absorption spectroscopy after beverage exposure. The effect of beverages on the enamel surface was visualized by scanning electron microscopy (SEM). Distilled water, and cola drinks were used as negative and positive controls.

RESULTS

The kombuchas exhibited lower pH values (2.82-3.66) than the ice teas (2.94-4.86), but still higher than the cola drinks (2.48-2.54). The fluoride concentration varied between 0.05 and 0.46 ppm and for 7 beverages the concentration was below the detection limit. The calcium release for kombuchas was 198-746 mg/l, for ice teas 16.1-507 mg/l, and for cola drinks 57.7-71.9 mg/l. Twenty-two beverages had a significantly greater calcium release than the cola drinks (p = .009-.014). The surface etching of the enamel was seen in the SEM analysis after beverage exposure.

CONCLUSIONS

Tea-based beverages have even higher erosive potential than cola drinks. Kombuchas especially, displayed a considerable erosive potential.

Evaluating the pH of Various Commercially Available Beverages in Pakistan: Impact of Highly Acidic Beverages on the Surface Hardness and Weight Loss of Human Teeth

The objectives of this study were to investigate the pH of common beverages and to evaluate the effects of common acidic beverages on the surface hardness and weight loss of human tooth specimens. A total of 106 beverages were conveniently purchased from supermarkets in Karachi, Pakistan. Prior to evaluation, beverages were refrigerated or stored at room temperature in accordance with the manufacturers’ recommendations. Beverages were categorized into six groups: ‘Sports and Energy drinks’, ‘Water’, ‘Fruit Juices and Drinks’, ‘Sodas’, ‘Milk and Flavored Milk’ and ‘Teas and Coffee’. Using a pH meter, the pH of each beverage was measured in triplicate at room temperature. In addition, the influence of five highly acidic beverages on the weight loss and surface hardness of human tooth specimens was evaluated using gravimetric analysis and the Vickers hardness tester, respectively. ‘Sports and Energy drinks’, ‘Fruits Juices and Drinks’ and ‘Sodas’ were the most acidic beverage categories, with a pH range of 3.00−5.00. A total of 33% of beverages tested in this study were highly acidic (pH less than 4.00), 29% of beverages were moderately acidic (pH 4.00−4.99) and 31% were mildly acidic (pH 5.00−6.99). Significant weight loss was observed in all immersed specimens compared to control counterparts (p < 0.05). Similarly, for surface hardness, five highly acidic beverages (Red Bull, Pepsi, Apple Cidra, Tang Mosambi and Tang Orange) significantly decreased the surface hardness of specimens (p < 0.05). The pH levels of commonly available beverages in Pakistan are highly acidic, which may encourage loss of minerals from teeth; hence, affecting their surface hardness.

Comparative evaluation of various herbal extracts on biofilms of Streptococcus mutans and Scardovia wiggsiae: An in vitro study

BACKGROUND

Owing to their strong antimicrobial properties, Helichrysum arenarium (HA), Anzer thyme (AT), and Stevia rebaudiana (SR) have been commonly used in medicine.

AIM

This study aimed to evaluate antimicrobial activities of HA, AT, and SR against S. mutans and S. wiggsiae in biofilms formed on primary teeth.

DESIGN

Fifty enamel samples were divided into two groups: mono-species biofilm and two-species biofilm. Each biofilm group was divided into five subgroups (n = 5): group 1, HA; group 2, AT; group 3, SR; group 4, CHX (positive control); and group 5, distilled water (negative control). Minimum inhibitory concentration and minimum bactericidal concentration were determined. The number of viable microorganisms was counted. The presence of microorganisms was examined using a scanning electron microscope, and mineral analysis was performed using energy-dispersive X-ray analysis.

RESULTS

In the mono-species biofilm, CHX was significantly more effective against S. mutans than other groups (p < .001). Furthermore, HA, AT, and SR groups showed significantly lower colony counts of S. mutans than distilled water (p < .05). In the two-species biofilm group, AT, SR, and CHX were significantly more effective against S. wiggsiae than distilled water (p < .05).

CONCLUSIONS

HA, AT, and SR have been suggested as effective natural alternatives to CHX against cariogenic bacteria.

Efficacy of Two Toothpaste in Preventing Tooth Erosive Lesions Associated with Gastroesophageal Reflux Disease

Patients suffering from acid reflux due to endogenous causes are often affected by gastroesophageal reflux disease which, in the oral environment, causes lingual and palatal enamel erosion. As enamel does not have the intrinsic ability to repair itself, the application of alloplastic materials, such as toothpastes is suggestable. The aim of this “in vitro” study was to compare the effectiveness of two different toothpastes in preventing erosion due to gastroesophageal reflux disease. Six tooth elements from bovine jaws were prepared using a high-speed diamond bur and water irrigation. Acid attack simulation was carried out using a 15% HCl hydrochloric acid solution. After that, two different toothpastes with or without fluoride, were brushed at the sample surface using an electric toothbrush at standard position and force. SEM and profilometer analysis were performed. Statistically significant difference was found in average tooth surface roughness after using toothpaste with or without fluoride after the acid attack, as the former offered a greater remineralization. No difference was found in long-term prevention. Fluoridated toothpastes offer a greater degree of remineralization at a first acid attack, however, there is no difference in long-term prevention independently from the toothpaste type.

Efficacy of silver diamine fluoride and sodium fluoride in inhibiting enamel erosion: an ex vivo study with primary teeth

PURPOSE

To assess the efficacy of silver diamine fluoride (SDF) and sodium fluoride (NaF) in inhibiting enamel erosion in primary teeth.

METHODS

80 primary canine teeth were immersed for 24 h in 2% NaF, 10% SDF, or distilled water. Afterward, some of them underwent a 10-min acid challenge using either 1% or 10% citric acid while others did not. Specimens selected for negative controls were immersed in distilled water but not exposed to the acids, whereas those selected for positive controls were not only immersed in distilled water, but also exposed to the acids. Following, 3-mL samples were collected for calcium and phosphorus analysis by an atomic emission spectrometer.

RESULTS

1% acid caused higher phosphorus loss in the positive control group than in the others (no differences between them). Regarding 10% acid, the SDF group showed lower phosphorus loss compared to the positive control and NaF groups. From calcium loss analysis, SDF and NaF groups presented no significant difference when compared to the positive control groups after both acidic challenges.

CONCLUSION

Considering phosphorus loss values, 10% SDF seems to be effective in inhibiting enamel erosion after 1% and 10% citric acid challenges, whereas 2% NaF only after 1% citric acid challenge. Regarding calcium loss values, both fluoride agents seem to have no impact on inhibiting enamel erosion after 1% and 10% citric acid challenges.

The Effect of Er:YAG Laser Irradiation Combined With Fluoride Application on the Resistance of Primary and Permanent Dental Enamel to Erosion

Introduction: Erosion is an important cause of tooth mineral loss. The combined use of lasers and fluoride has been introduced as a novel modality for the prevention of enamel demineralization. This study aimed to assess the effect of Er:YAG laser combined with fluoride application on primary and permanent enamel resistance to erosion. Methods: Eighty enamel specimens of permanent (n=40) and primary (n=40) molars were prepared and randomly assigned to 4 groups: C-control (no pretreatment), F-acidulated phosphate fluoride (APF) gel, FL-APF gel application followed by Er:YAG laser irradiation, and LF-Er:YAG laser irradiation followed by the application of APF gel . The specimens were then submitted to pH cycling using Coca-Cola (pH=2.4). Enamel micro-hardness was measured using the Vickers microhardness tester before pretreatment and after the erosive process. The collected data were analyzed using the Kolmogorov-Smirnov test, two-way ANOVA and repeated measures ANOVA. Results: The micro-hardness of both permanent and primary enamel specimens significantly decreased after the erosive process (P < 0.05). In the permanent enamel specimens, the greatest reduction in micro-hardness was noted in groups C and F, while the least reduction was noted in group FL. However, these differences were not statistically significant (P > 0.05). In the primary enamel specimens, the greatest reduction in micro-hardness was noted in groups C and LF, while the least reduction was noted in group F. These differences were not statistically significant (P > 0.05). Conclusion: Within the limitations of this study, Er:YAG laser irradiation combined with fluoride application could not prevent erosion in permanent and primary enamel during the erosive process.

Evaluating the buffering and acid-resistant properties of eggshell-titanium dioxide composite against erosive acids

OBJECTIVE:

This paper reports on the buffering and acid-resistant properties of a modified eggshell-titanium composite against citric acid attack.

MATERIALS AND METHODS:

Eggshell-titanium EB-TiO₂ was prepared by ball-milling eggshell powder and titanium dioxide. Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM) were used to characterize EB-TiO₂. The buffering property against citric acid at pH values of 2, 4, and 5 was measured using a pH meter. Five brands of toothpaste (Colgate, Colgate Sensitive, Aquafresh, Oralwise, and Sensodyne) were used to assess the acid-resistant properties of EB-TiO₂. Enamel models were simulated by dissolving each brand of toothpaste with eggshell (control) and EB-TiO₂. The samples were exposed to citric acid of pH 2. The average slope (kPa/s) was measured using a pressure sensor. An analysis of variance was used to analyze the kPa/s values (α =.05).

RESULTS:

The FTIR and XRD analyses suggest the surface modification of EB-TiO₂. The TEM image revealed spherical-shaped particles in EB-TiO₂. The pH test results showed that the buffering properties of eggshell and EB-TiO₂ were comparable. Significant differences were observed in the acid resistance properties of the samples exposed to citric acids ( P < .05). The Colgate toothpaste infused with eggshell powder had the highest mean kPa/s values, whereas Sensodyne infused with EB-TiO₂ had the lowest kPa/s values.

CONCLUSION:

The salient features of this study indicate that modification of eggshell with titanium dioxide does not affect its carbonate buffering properties. Connecting the kPa/s values to acid-resistant properties, EB-TiO₂ effectively reduces erosive attacks when added to toothpaste.

An In Situ Evaluation of the Protective Effect of Nano Eggshell/Titanium Dioxide against Erosive Acids

OBJECTIVES

Enamel erosion caused by high consumption of acidic drinks poses a significant public health concern. This study was aimed to determine the protective effect of eggshell-titanium dioxide composite (EB@TiO2) against erosive acids on tooth enamel.

METHODS

Twenty prepared bovine tooth enamel specimens were randomly assigned to 5 sample groups (n=4): (1) unexposed tooth enamel; (2) exposed tooth enamel + HCI; (3) exposed tooth enamel + HCI + Colgate toothpaste; (4) exposed tooth enamel + HCI + Sensodyne toothpaste; and (5) exposed tooth enamel + HCI + EB@TiO2. The mean roughness value (R rms) of the exposed and unexposed tooth was measured with atomic force microscope (AFM). Scanning electron microscope (SEM) and Raman spectroscopy techniques were used to evaluate the surface morphology and changes. ANOVA was used to analyze the mean square roughness (R rms) values for all specimens. Bonferonni correction was used to identify the mean differences among the 5 groups (α=0.05). The R rms values measured for the unexposed and exposed specimens in HCI alone were statistically significant (P < 0.05).

RESULTS

No significant differences were found for the unexposed and exposed specimens in HCI + toothpaste and EB@TiO2. The tooth enamel specimens exposed to HCI + Sensodyne had the highest R rms values, while specimens exposed to HCI + EB@TiO2 had the lowest R rms values.

CONCLUSIONS

This study confirms that the investigated toothpaste provides protection against acidic substances. The study results further suggests that EB@TiO2 could be used to provide enhanced protection for tooth enamel.

In vitro simulation of erosive challenges to human enamel using a novel artificial mouth

This in vitro work reports upon the design, build and operation of an artificial environment (Saltus) that sought to simulate the process of in vivo dental erosion upon human enamel. A novel testing environment, housed 8 erosion testing substrate specimens, that on separate occasions were subject to 4 different experimental diets, of increasing erosive challenge, simulating the consumption of an acidic beverage. Each set of specimens was subjected to one of the experimental diets only. These were liquid only and administered the test beverage over a standardized range of volumes and durations. Flow of both artificial unstimulated and stimulated saliva was maintained throughout and the effects upon the substrates were measured by profilometry, surface microhardness determination and chemical analysis of the saliva and beverage mixture for traces of Calcium and Phosphate ions. The overall trend of surface hardness reduction, depth of surface loss and ion loss across the diets increased in proportion to the severity of insult. Accepting the limitations of this study Saltus appeared to perform well as an environment in which to simulate and assess dental erosion using parameters defined by previous in vivo observations of human drinking behaviour. The authors however acknowledge that in vitro testing can never replicate fully the in vivo situation.

Prevention of erosive tooth wear: targeting nutritional and patient-related risks factors

This article provides an overview of the nutritional and patient-related risk factors involved in the aetiology of erosive tooth wear (ETW) and the preventive strategies to counteract them. The first step is to diagnose clinical signs of ETW and to recognise causal factors. Low pH and high buffer capacity of foods/drinks are the major risk factors, while the calcium concentration is the main protective factor. Reduction of frequency of consumption and contact time of erosive foods/drinks with the teeth, use of straws appropriately positioned and consumption of dairy products are advisable. Oral hygiene has a role in the development of ETW, however, postponing toothbrushing is not clinically advisable. In cases of drug abuse, chronic alcoholism, GERD or bulimia, the patient must be referred to a doctor. Immediately after vomiting, patients might be advised to rinse the mouth. Saliva has an important protective role and patients with reduced salivary flow can benefit from the use of chewing gum. Recent studies have focused on improving the protective capacity of the acquired pellicle as well as on the role of protease inhibitors on dentine erosion. However, the degree of evidence for these preventive measures is low. Clinical trials are necessary before these measures can be recommended.

Fluoride toothpastes containing micrometric or nano-sized sodium trimetaphosphate reduce enamel erosion in vitro

OBJECTIVE

To evaluate the effect of fluoride toothpastes supplemented with micrometric or nano-sized sodium trimetaphosphate (TMP or TMPnano, respectively) on enamel erosion in vitro, as well as the influence of salivary acquired pellicle and saliva.

MATERIAL AND METHODS

Bovine enamel blocks (n = 120) were randomly assigned into the following experimental toothpastes: no F/TMP/TMPnano (Placebo); 1100 ppm F (1100 ppm F); 1100 ppm F plus 3% TMP or 3% TMPnano (1100 TMP or 1100 TMPnano, respectively) and 5000 ppm F (5000 ppm F). Erosive challenge was performed by immersion of the blocks in citric acid for 5 min, followed by 2 h immersion in human or artificial saliva, 4×/day, during 5 days. After each erosive challenge, blocks were exposed to slurries of the toothpastes. Enamel erosion (µm), surface hardness (SHf) and cross-sectional hardness (ΔKHN) were analyzed as response variables and the data were submitted to two-way ANOVA, followed by the Student-Newman-Keuls test (p < .05).

RESULTS

1100 TMPnano significantly reduced enamel loss when compared to 1100 TMP (p = .002), reaching values similar to those promoted by 5000 ppm F (p = .96). 1100 ppm F presented significantly lower enamel loss than Placebo (p < .001), and higher than 1100 TMP (p < .001). Significantly higher SHf and lower ΔKHN was observed for 1100 TMPnano and 5000 ppm F when compared with the other groups (p < .001). The type of saliva did not influence enamel erosion, SHf and ΔKHN for the groups treated with TMP-containing toothpastes.

CONCLUSION

The addition of 3% TMPnano to 1100 ppm F toothpastes significantly increases the protective effect against enamel erosion in vitro when compared with its counterparts with micrometric TMP or without TMP. This effect was not influenced by the presence of acquired enamel pellicle and saliva.

Effects of tannin-fluoride and milk-fluoride mixture on human enamel erosion from inappropriately chlorinated pool water

This in vitro study aimed to investigate the efficacy of tannin-fluoride and milk-fluoride mixtures on human enamel erosion after exposure to inappropriately chlorinated pool water. Enamel specimens were immersed in swimming pool water (pH 2.7) for 30 min and in each test reagent for 4 min once a day for 60 consecutive days (group I: control, group II: tannin-fluoride, group III: milk-fluoride, group IV: tannin-fluoride before and milk-fluoride after erosive challenge, and group V: milk containing tannin-fluoride before and after erosive exposure). Surface microhardness was assessed on days 0, 30, and 60. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were performed after treatment of samples for 60 days. Surface microhardness of experimental groups was ranked as follows: group III > group IV-group V > group II > group I (P < 0.05). Moreover, SEM images revealed deposition of substances on erosive enamel surface after treatment with tannin-fluoride and milk-fluoride mixtures. Furthermore, EPMA profiles showed decrease of phosphorus and increase of fluoride content in groups II and IV. In conclusion, we demonstrated that treatment with fluoridated milk with or without tannin-fluoride has protective effects against enamel erosion caused by low-pH swimming pool water.

Effect of a Bioactive Glass Ceramic on the Control of Enamel and Dentin Erosion Lesions

Abstract This study evaluated the effect of a bioactive glass ceramic for the control of erosion and caries lesions. Fragments (n=10) of bovine enamel and root dentin received daily application of different treatments (Biosilicate; Acidulated Phosphate Fluoride- APF; Untreated - control) during the performance of erosive cycles. Surfaces were analyzed with 3D optical profilometry to quantify the superficial loss in four periods (1, 7, 14 and 21 days), as well as the lesion depth with confocal laser scanning microscopy. For caries progression assessment, initial Knoop microhardness was measured on enamel bovine fragments. Initial carious lesions were developed and specimens were divided into three groups (n=10), according to the daily topical application (Biosilicate; APF; no application - control), during the de-remineralization cycles for 14 days. Final microhardness was obtained to calculate the change of surface microhardness. Subsurface demineralization was analyzed using cross-sectional microhardness (depths 10, 30, 50, 70, 90, 110 and 220 µm). Data were tested using ANOVA and Tukey’s test (a=5%). Results of erosive evaluation showed that Biosilicate promoted the lowest (p<0.05) values of surface loss, regardless of time, for both enamel and dentin; APF promoted lower (p<0.05) surface loss than control; analyzing different periods of time, APF did not show difference (p>0.05) between 14 and 21 days of demineralization. Results of enamel caries assessment showed that Biosilicate resulted in higher (p<0.05) surface and subsurface microhardness than both APF and control-applications. It may be concluded that Biosilicate application showed a higher potential to reduce surface loss and development of erosion and caries lesions.

Impact of CO2 laser and stannous fluoride on primary tooth erosion

This study evaluated in vitro the effect of input power of CO2 laser, either associated or not to stannous fluoride (SnF2) gel, for the control of intrinsic erosion in primary teeth. One hundred four enamel slabs (3 × 3 × 2 mm) from human primary molars were flattened and polished. Adhesive tapes were placed on their surface leaving a window of 3 × 1 mm. Slabs were then cycled four times in 0.01 M hydrochloric acid (pH 2, 2 min) and in artificial saliva (2 h) for creation of erosive lesions. Specimens were randomly assigned into eight groups (n = 13) according to fluoride application [absent (control) or 0.4% stannous fluoride gel (SnF2)] and input power of CO2 laser [unlased (control), 0.5, 1.0 or 1.5 W]. The CO2 laser irradiation was performed in an ultra-pulse mode (100 μs of pulse duration), 4-mm working distance, for 10 s. Specimens were then submitted to further erosive episodes for 5 days and evaluated for enamel relative permeability. Fluoride did not show any protective effect for any of the laser-treated groups or control (p = 0.185). However, a significant effect was detected for input power of CO2 laser (p = 0.037). Tukey's test showed that there was a significant statistically difference between specimens irradiated with 0.5 and 1.5 W (p = 0.028). The input power of 0.5 W showed lower permeability. Variation of input power CO2 laser can influence enamel permeability, at the power of 1.5 W which promoted greater permeability.

The pH of beverages in the United States

BACKGROUND

Dental erosion is the chemical dissolution of tooth structure in the absence of bacteria when the environment is acidic (pH < 4.0). Research indicates that low pH is the primary determinant of a beverage's erosive potential. In addition, citrate chelation of calcium ions may contribute to erosion at higher pH. The authors of this study determined the erosive potential measured by the pH of commercially available beverages in the United States.

METHODS

The authors purchased 379 beverages from stores in Birmingham, Alabama, and categorized them (for example, juices, sodas, flavored waters, teas, and energy drinks) and assessed their pH. They used a pH meter to measure the pH of each beverage in triplicate immediately after it was opened at a temperature of 25°C. The authors recorded the pH data as mean (standard deviation).

RESULTS

Most (93%, 354 of 379) beverages had a pH of less than 4.0, and 7% (25 of 379) had a pH of 4.0 or more. Relative beverage erosivity zones based on studies of apatite solubility in acid indicated that 39% (149 of 379) of the beverages tested in this study were considered extremely erosive (pH < 3.0), 54% (205 of 379) were considered erosive (pH 3.0 to 3.99), and 7% (25 of 379) were considered minimally erosive (pH ≥ 4.0).

CONCLUSIONS

This comprehensive pH assessment of commercially available beverages in the United States found that most are potentially erosive to the dentition.

PRACTICAL IMPLICATIONS

This study's findings provide dental clinicians and auxiliaries with information regarding the erosive potential of commercially available beverages. Specific dietary recommendations for the prevention of dental erosion may now be developed based on the patient's history of beverage consumption.

Amazonian delicacy tucupi is as erosive as a cola-based soft drink

OBJECTIVE

Acidic diets are advocated as main risk factor for tooth erosion, which could be prevented, or at least controlled, if patients were early advised. It is important to identify, hence, if possible dietary constituents regionally consumed on large scale, such as tucupi, a low-pH yellowish-green color and strong flavor delicacy made from the juice of a bitter cassava, may explain its occurrence in specific patient groups. This cross-over in situ/ex vivo study evaluated tucupi's ability to promote erosion of bovine enamel by assessing its percentage of surface microhardness change (%SMHC), taking a cola-based soft drink and human saliva as positive and negative controls.

DESIGN

For three 7-days spaced out legs of 7 days each, nine volunteers wore palatal devices with three bovine enamel blocks, which were challenged with one of the following solutions: TUC-tucupi (n=27); COL-cola-based soft drink (n=27); SAL-saliva (n=27). Erosive challenges were performed extra-orally (4×/day) by dropping TUC or COL at room temperature on specimens. After 5min, palatal devices were replaced into the mouth. SAL permanently acted as the negative control while volunteers solely wore the device. One-way ANOVA followed by Tukey's post-hoc tests (α=0.05) were applied.

RESULTS

TUC promoted an enamel %SMHC (-21.56±10.08(a)) similar than that promoted by COL (-18.19±12.99(a); p=0.275), which were both significantly higher than that promoted by SAL (-1.86±13.65(b); p<0.0001).

CONCLUSIONS

Besides the most worldwide appreciated cola-based soft drink, the greatly consumed Amazonian delicacy tucupi can be considered a potential risk factor for tooth erosion.

CO₂ laser emission modes to control enamel erosion

Considering the importance and prevalence of dental erosion, the aim of this in vitro study was to evaluate the influence of different modes of pulse emission of CO2 laser associated or not to acidulated phosphate fluoride (APF) 1.23% gel, in controlling enamel erosion by profilometry. Ninety-six fragments of bovine enamel were flattened and polished, and the specimens were subjected to initial erosive challenge with hydrochloric acid (pH = 2). Specimens were randomly assigned according to surface treatment: APF 1.23% gel and gel without fluoride (control), and subdivided according to the modes of pulse CO2 laser irradiation: no irradiation (control), continuous, ultrapulse, and repeated pulse (n = 12). After surface treatment, further erosive challenges were performed for 5 days, 4 × 2 min/day. Enamel structure loss was quantitatively determined by a profilometer, after surface treatment and after 5 days of erosive challenges. Two-away ANOVA revealed a significant difference between the pulse emission mode of the CO2 laser and the presence of fluoride (P ≤ 0.05). The Duncan's test showed that CO2 laser irradiation in continuous mode and the specimens only received fluoride, promoted lower enamel loss than that other treatments. A lower dissolution of the enamel prisms was observed when it was irradiated with CO2 laser in continuous mode compared other groups. It can be concluded that CO2 laser irradiation in continuous mode was the most effective to control the enamel structure loss submitted to erosive challenges with hydrochloric acid.

Possible ways of reducing dental erosive potential of acidic beverages

Frequent consumption of acidic beverages is related to excessive tooth wear, namely dental erosion. Preventive measures may involve reduction or elimination of acidic drink consumption. However, the success of this approach is difficult to achieve as it is highly dependent on patient compliance. Therefore, a practical way of minimizing the erosive potential of popular acidic drinks may be their chemical modification. The aim of this article was to review the different methods of modification and their shortcomings. The available literature demonstrates that the erosive potential of most acidic beverages could be reduced. To date, the effectiveness of soluble calcium salts supplementation is the best established. However, modification can reduce the sensorial quality of the drink and shorten its shelf-life. There is also a need to evaluate the lowest effective and safe dose of the additive.

Er:YAG laser irradiation to control the progression of enamel erosion: an in situ study

This in situ study evaluated the effect of Er:YAG laser irradiation in controlling the progression of enamel erosion-like lesions. Fifty-six enamel slabs (330 KHN ± 10 %) with one fourth of the surface covered with resin composite (control area) were submitted to initial erosion-like lesion formation with citric acid. The slabs were divided into two groups: irradiated with Er:YAG laser and non-irradiated. Fourteen volunteers used an intraoral palatal appliance containing two slabs, in two phases of 5 days each. During the intraoral phase, in a crossed-over design, half of the volunteers immersed the appliance in citric acid while the other half used deionized water, both for 5 min, three times per day. Enamel wear was determined by an optical 3D profilometer. ANOVA revealed that when deionized water was used as immersion solution during the intraoral phase, lower values of wear were showed when compared with the groups that were eroded with citric acid, whether irradiated or non-irradiated with Er:YAG laser. When erosion with citric acid was performed, Er:YAG laser was not able to reduce enamel wear. Small changes on enamel surface were observed when it was irradiated with Er:YAG laser. It may be concluded that Er:YAG laser irradiation did not reduce the progression of erosive lesions on enamel submitted to in situ erosion with citric acid.

A randomised in situ trial, measuring the anti-erosive properties of a stannous-containing sodium fluoride dentifrice compared with a sodium fluoride/potassium nitrate dentifrice

OBJECTIVES

To determine if a stabilised, stannous-containing sodium fluoride dentifrice provides greater enamel protection in situ against intraoral dietary erosive challenges compared with a sodium fluoride/potassium nitrate dentifrice.

METHODS

A single-centre, investigator blind, randomised, supervised, two-treatment, non-brushing, four-period crossover in situ study was undertaken, with each test period being 15 days. Thirty-five healthy adult subjects were recruited to participate in the study, which included four erosive acid challenges per day. Subjects were randomised to product treatment, which included either: (1) a stannous-containing sodium fluoride dentifrice (Oral-B(®) Pro-Expert Sensitive) or (2) a sodium fluoride/potassium nitrate dentifrice (Sensodyne(®) Pronamel(®) ). Each study subject wore an intraoral appliance retaining two sterilised, polished human enamel samples for 6 hours/day. Subjects swished with an allocated dentifrice slurry twice a day and with 250 ml of orange juice for 10 minutes (25 ml/minute over a 10-minute period) four times per day. The primary and secondary outcomes for this study were enamel loss measured using contact profilometry at days 15 and 5, respectively, using parametric analysis methods.

RESULTS

At day 15, a 38% lower enamel loss (P < 0.0001) was observed, with estimated medians of 2.03 μm (SE 0.247) and 3.30 μm (SE 0.379), in favour of the stannous-containing dentifrice. At day 5, specimens treated with the stannous-containing sodium fluoride dentifrice demonstrated 25% less enamel loss than those treated with the sodium fluoride/potassium nitrate dentifrice. Treatment differences at day 5 were also statistically significant (P < 0.05), with estimated medians of 1.37 μm (SE 0.177) and 1.83 μm (SE 0.223), respectively.

CONCLUSIONS

Results of this in situ study suggest the stabilised, stannous-containing sodium fluoride dentifrice could be used to provide significantly greater protection to enamel from erosive acid challenge compared with that provided by conventional fluoride-containing products.

Calcium lactate pre-rinse increased fluoride protection against enamel erosion in a randomized controlled in situ trial

OBJECTIVES

This in situ trial study was designed to evaluate whether calcium (Ca) pre-rinse would increase the fluoride (F) rinse protection against enamel erosion.

METHODS

Fifteen volunteers participated in this split-mouth, 3-phase, crossover design study wearing a palatal appliance containing four sterilized bovine enamel slabs, for 10 days. In the 1st phase, five participants followed protocol A: daily rinse with a Ca lactate (CaL, 150mmol/L, 1min), followed by F (NaF 12mmol/L, 1min). Other five participants followed protocol B: daily rinse only with F, while the remainders followed protocol C: no rinse (negative control). Appliances were removed from the mouth and one side of the palatal appliance was exposed to a daily erosive challenge (0.05M citric acid, 90s); the other side served as control (deionized water - no erosion). In the 2nd phase volunteers were crossed over to other protocol and in the 3rd phase volunteers received the remaining protocol not yet assigned. Specimens were evaluated for surface loss using an optical profilometer.

RESULTS

Repeated-measures three-way ANOVA (p=0.009) and Tukey's test showed that CaL pre-rinse followed by NaF rinse significantly decreased surface loss of enamel when performed prior to an erosive challenge in comparison with the condition in which NaF only was used.

CONCLUSIONS

Pre-rinse with CaL may increase the protection exerted by NaF against erosive wear.

Effect of beverages on bovine dental enamel subjected to erosive challenge with hydrochloric acid

This study evaluated by an in vitro model the effect of beverages on dental enamel previously subjected to erosive challenge with hydrochloric acid. The factor under study was the type of beverage, in five levels: Sprite® Zero Low-calorie Soda Lime (positive control), Parmalat® ultra high temperature (UHT) milk, Ades® Original soymilk, Leão® Ice Tea Zero ready-to-drink low-calorie peach-flavored black teaand Prata® natural mineral water (negative control). Seventy-five bovine enamel specimens were distributed among the five types of beverages (n=15), according to a randomized complete block design. For the formation of erosive wear lesions, the specimens were immersed in 10 mL aqueous solution of hydrochloric acid 0.01 M for 2 min. Subsequently, the specimens were immersed in 20 mL of the beverages for 1 min, twice daily for 2 days at room temperature. In between, the specimens were kept in 20 mL of artificial saliva at 37ºC. The response variable was the quantitative enamel microhardness. ANOVA and Tukey's test showed highly significant differences (p<0.00001) in the enamel exposed to hydrochloric acid and beverages. The soft drink caused a significantly higher decrease in microhardness compared with the other beverages. The black tea caused a significantly higher reduction in microhardness than the mineral water, UHT milk and soymilk, but lower than the soft drink. Among the analyzed beverages, the soft drink and the black tea caused the most deleterious effects on dental enamel microhardness.

On inhibition of dental erosion

OBJECTIVE

To examine the erosion-inhibiting effect of different concentrations of hydrofluoric acid.

MATERIALS AND METHODS

Thirty-six human molars were individually treated with 10 ml of 0.1 M citric acid for 30 min (Etch 1), acid was collected and stored until analysis. The teeth were randomly divided into six groups and then individually treated with 10 ml of one of six dilutions (from 0.1-1%) of hydrofluoric acid. The teeth were then again treated with citric acid (Etch 2). The individual acid samples from Etch 1 and 2 were analyzed for calcium by flame atomic absorption spectroscopy and difference in calcium loss was calculated.

RESULTS

The highest erosion inhibiting effect was obtained in groups with the highest concentrations of hydrofluoric acid, where the pH was lowest, below pKa of 3.17, thus the hydrofluoric acids being mainly in an undissociated state.

DISCUSSION

Diluted hydrofluoric acid is present in aqueous solution of SnF2 and TiF4 (which are known to inhibit dental erosion): SnF2 + 3H2O = Sn(OH)2 + 2HF + H2O and TiF4 + 5H2O = Ti(OH)4 + 4HF + H2O. It is also known that pure, diluted hydrofluoric acid can inhibit dental erosion. Teeth treated with hydrofluoric acid are covered by a layer of CaF2-like mineral. This mineral is acid resistant at pH < 3, because it was formed at this pH.

CONCLUSION

The erosion-inhibiting effect is due to formation of an acid resistant mineral, initiated by tooth enamel treatment with hydrofluoric acid. Hydrofluoric acid is different in having fluoride as a conjugated base, which provides this acid with unique properties.

Saliva and dental erosion

Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear.

OBJECTIVE

This review discusses the role of salivary factors on the development of dental erosion.

MATERIAL AND METHODS

A search was undertaken on MeDLINe website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party.

RESULTS

Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion.

CONCLUSIONS

Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects.

Effect of fluoride on tooth erosion around orthodontic brackets

The aim of the present study was to evaluate the effect of fluoride in prevention of tooth erosion around orthodontic brackets under erosive challenge. Edgewise brackets were bonded with Transbond™ XT composite on vestibular surface of 40 bovine incisors. The teeth were assigned to 4 groups (n=10): G1: Remineralizing saliva; G2: Erosive challenge; G3: Experimental group submitted to topical application of neutral fluoride gel (2% NaF) before erosive challenge; G4: Experimental group submitted to three daily applications of fluoride dentifrice (PFM 1500 ppmF) during erosive challenge. After 14 days of erosive challenge, direct visual and tactile examination were performed by two calibrated and trained examiners (Kappa = 0.867). The following scores were used: 0 = Intact enamel, 1 = Demineralized enamel without cavity, 2 = Demineralized enamel with cavity, 3 = Remineralized enamel without cavity, 4 = Remineralized enamel with cavity. Kruskal-Wallis and Mann-Whitney tests were applied to determine erosion levels, establishing a confidence interval of 95% (p<0.05). G2 and G3 presented 100% of score 2, with large cavities, presenting rough and opaque surface. G4 showed 50% of score 3 and 50% of score 4. Considering the studied conditions, it was found a significant difference between G2 and G4 and between G3 and G4 (p<0.01). By contrast to single application of neutral fluoride gel, the high frequency of use of fluoride at low concentration had a great influence during the dynamics of erosion.

Estimated erosive potential depends on exposure time

OBJECTIVES

Evaluate erosive potential of beverages, using exposure times from 3 to 30 min, and to analyse the relationship between erosion and several drink parameters.

METHODS

pH, calcium, phosphate and fluoride concentration, saturation, titratable-acidity to pH 5.5 and the viscosity of sixteen beverages were measured or calculated. Enamel samples (N = 90) were serially exposed to 1 ml of the beverages for 3, 6, 9, 15 and 30 min and erosion was measured as the loss of calcium to the beverage. Rate of erosion per min was calculated by linear curve fitting using all exposure times. Linear regression analysis was performed to determine the correlation between erosion and the drink parameters. A limited multivariate analysis was performed for the outcome parameter with the highest univariate correlations (erosion per minute) and 4 drink variables.

RESULTS

A negative relationship was observed only for pH for all exposure times. Only for erosion per min a significant relationship with pH and saturation was found. In a model for erosion per min using only saturation, fluoride concentration, titratable acidity and viscosity, both saturation and viscosity were shown to have a significant effect (p = 0.01 and p = 0.05, respectively).

CONCLUSION

Exposure times between 3 and 30 min result in very different estimates of erosive potential. There is no sound theoretical ground for preferring one or other exposure time/outcome as being more clinically relevant.

CLINICAL RELEVANCE

This study shows that effect of the choice of study methodology on the measurement of erosive potential of beverages is large.

Erosive potential of different types of grape juices

The purpose of the present study was to evaluate the erosive potential of different types (concentrated and powdered) and commercial brands of industrialised grape juices. The pH of all five fruit drinks was measured at two time points: immediately after preparation and 24 hours later. Sixty specimens of bovine enamel were randomly allocated and immersed in different types of grape juice (n = 10) for 10 minutes four times a day for fifteen days. The enamel alteration was analysed using surface Knoop microhardness (KHN) and surface roughness (Ra) tests at baseline and on the 5(th), 10(th) and 15(th) days of the experiment. Two way ANOVA, Tukey's post hoc and Pearson's correlation tests were used for statistical analysis (α = 5%). The grape juices presented pH values ranging from 2.9 to 3.5. All of the tested juices promoted significant enamel mineral loss (p < 0.05) on the first evaluation (5(th) day of immersion) and produced a significant increase in the mean roughness from the 10(th) day on when compared to the control group (p < 0.05). By the 15(th) day, all of the beverages had produced surface roughnesses that were significantly higher than that of the control group. The results suggest that all grape juices, regardless of their commercial presentation, present erosive potential.

Dental erosion and its growing importance in clinical practice: from past to present

Since the mid-1990s, the focus of studies on tooth wear has steadily shifted from the general condition towards the more specific area of dental erosion; equally, a shift has occurred from studies in adults to those in children and adolescents. During this time, understanding of the condition has increased greatly. This paper attempts to provide a critical overview of the development of this body of knowledge, from earlier perceptions to the present. It is accepted that dental erosion has a multifactorial background, in which individual and lifestyle factors have great significance. Notwithstanding methodological differences across studies, data from many countries confirm that dental erosion is common in children and young people, and that, when present, it progresses rapidly. That the condition, and its ramifications, warrants serious consideration in clinical dentistry, is clear. It is important for the oral healthcare team to be able to recognize its early signs and symptoms and to understand its pathogenesis. Preventive strategies are essential ingredients in the management of patients with dental erosion. When necessary, treatment aimed at correcting or improving its effects might best be of a minimally invasive nature. Still, there remains a need for further research to forge better understanding of the subject.

Role of titanium tetrafluoride (TiF(4)) in conservative dentistry: A systematic review

The role of fluoride to reduce demineralization and enhance remineralization of dental hard tissue has been well documented. Different forms of fluoride solutions have been topically used in dentistry as prophylactic agents against tooth decay. In the recent past, metal fluorides, especially titanium tetrafluoride, have become popular in the fraternity of dental research due to their unique interaction with dental hard tissue. Many studies on titanium tetrafluoride, with positive and negative conclusions, have been published in many research journals. This gives the reader a plethora of inconclusive results with one study neutralizing the outcome of other, which confuses us regarding the present status of titanium tetrafluoride in the field of dentistry. This is an endeavor to organize and present the various studies of this unique compound, to provide us with a lucid overall review of its versatile potential application in dentistry, along with its fallacy/drawbacks. We have discussed its role as a cariostatic agent, pit and fissure sealant, tooth desensitizer, against dental erosion, as a root canal irrigant and others.

A qualitative and quantitative investigation into the effect of fluoride formulations on enamel erosion and erosion-abrasion in vitro

OBJECTIVES

To investigate the effect of a single application of highly concentrated SnF(2) and NaF solutions and a NaF/CaF(2) varnish on human enamel subjected to hydrochloric acid erosion and tooth brush abrasion.

METHODS

Forty enamel samples were prepared from human third molars and NaF (9500ppm, pH 8.0), SnF(2) (9500ppm, pH 2.6) solutions; Bifluorid10(®) varnish (42,500ppm, NaF 5%, CaF(2) 5%) and deionized water (control) was applied to the enamel. Following this three, six and nine cycles of erosion [1 cycle=erosion (0.01M HCl, pH 2.2, 2min)+artificial saliva (1h, pH 7.0)] and erosion-abrasion [1 cycle=erosion (0.01M HCl, pH 2.2, 2min)+artificial saliva (1h, pH 7.0)+abrasion (120 linear strokes in artificial saliva from Tepe medium soft brushes 200g loading)] were carried out. The fluoride treated enamel was analysed using Knoop microhardness, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

RESULTS

For erosion alone, there was significantly less microhardness reduction in the Bifluorid10(®) group after three and six cycles of erosion (P<0.05), however no other groups showed statistically different hardness (P>0.05). The EDS analysis showed that only the Bifluorid10(®) group had any detectable fluorine following erosion and erosion-abrasion (0.1wt.% and 0.2wt.% fluorine respectively). The surface fluorine was found to have been removed after erosion and erosion-abrasion for all other surface treatments. Although precipitates were observed after application of the surface treatments, following erosion-abrasion, no visible surface effects from any fluoride preparation remained.

CONCLUSIONS

Enamel surface precipitates from application NaF, SnF(2) solutions appear to not be able to provide protection against gastric erosion and tooth brush abrasion. The NaF/CaF(2) varnish provided limited protection against erosion but the role for such varnishes in gastric erosion and tooth brush abrasion remains uncertain.

Analysis of the erosive effect of different dietary substances and medications. Br J Nutr. 2012;107:252-262. [PMID: 21733310 DOI: 10.1017/s0007114511002820]

Excessive consumption of acidic drinks and foods contributes to tooth erosion. The aims of the present in vitro study were twofold: (1) to assess the erosive potential of different dietary substances and medications; (2) to determine the chemical properties with an impact on the erosive potential. We selected sixty agents: soft drinks, an energy drink, sports drinks, alcoholic drinks, juice, fruit, mineral water, yogurt, tea, coffee, salad dressing and medications. The erosive potential of the tested agents was quantified as the changes in surface hardness (ΔSH) of enamel specimens within the first 2 min (ΔSH2-0 = SH2 min - SHbaseline) and the second 2 min exposure (ΔSH4-2 = SH4 min - SH2 min). To characterise these agents, various chemical properties, e.g. pH, concentrations of Ca, Pi and F, titratable acidity to pH 7·0 and buffering capacity at the original pH value (β), as well as degree of saturation (pK - pI) with respect to hydroxyapatite (HAP) and fluorapatite (FAP), were determined. Erosive challenge caused a statistically significant reduction in SH for all agents except for coffee, some medications and alcoholic drinks, and non-flavoured mineral waters, teas and yogurts (P < 0·01). By multiple linear regression analysis, 52 % of the variation in ΔSH after 2 min and 61 % after 4 min immersion were explained by pH, β and concentrations of F and Ca (P < 0·05). pH was the variable with the highest impact in multiple regression and bivariate correlation analyses. Furthermore, a high bivariate correlation was also obtained between (pK - pI)HAP, (pK - pI)FAP and ΔSH.

Impact of acquired enamel pellicle modification on initial dental erosion

The acquired enamel pellicle that forms on the tooth surface serves as a natural protective barrier against dental erosion. Numerous proteins composing the pellicle serve different functions within this thin layer. Our study examined the effect of incorporated mucin and casein on the erosion-inhibiting potential of the acquired enamel pellicle. Cyclic acidic conditions were applied to mimic the erosive environment present at the human enamel interface during the consumption of soft drinks. One hundred enamel specimens were prepared for microhardness tests and distributed randomly into 5 groups (n = 20) that received the following treatment: deionized water, humidity chamber, mucin, casein, or a combination of mucin and casein. Each group was exposed to 3 cycles of a 2-hour incubation in human saliva, followed by a 2-hour treatment in the testing solution and a 1-min exposure to citric acid. The microhardness analysis demonstrated that the mixture of casein and mucin significantly improved the erosion-inhibiting properties of the human pellicle layer. The addition of individual proteins did not statistically impact the function of the pellicle. These data suggest that protein-protein interactions may play an important role in the effectiveness of the pellicle to prevent erosion.

Can anti-erosion dentifrices also provide effective plaque control?

OBJECTIVE

While gingivitis and caries continue to be prevalent issues, there is growing concern about dental erosion induced by dietary acids. An oral hygiene product that protects against all these conditions would be beneficial. This study investigated the potential of two anti-erosion dentifrices to inhibit plaque.

METHODS

This was a randomized, three-period, two-treatment, double-blind, crossover study evaluating a stannous chloride/sodium fluoride dentifrice (SnCl(2)/NaF, blend-a-med(®) Pro Expert) and a popular anti-erosion dentifrice (NaF, Sensodyne(®) ProNamel(™)). During Period 3, subjects were randomized to repeat one treatment to evaluate any product carryover effects. Each treatment period was 17 days. Test dentifrices were used with a standard manual toothbrush. Digital plaque image analysis (DPIA) was employed at the end of each period to evaluate plaque levels (i) overnight (am prebrush); (ii) post-brushing with the test product (am post-brush); and (iii) mid-afternoon (pm). Analysis was conducted via an objective computer algorithm, which calculated total area of visible plaque.

RESULTS

Twenty-seven subjects completed the study. At all time points, subjects had statistically significantly (P ≤ 0.0001) lower plaque levels after using the SnCl(2)/NaF dentifrice than the NaF dentifrice. The antiplaque benefit for the SnCl(2)/NaF dentifrice versus the NaF dentifrice was: am prebrush = 26.0%; am post-brushing = 27.9%; pm = 25.7%.

CONCLUSIONS

The SnCl(2)/NaF dentifrice provided significantly greater daytime and overnight plaque inhibition than the NaF toothpaste. When recommending dentifrice to patients susceptible to dental erosion, clinicians can consider one that also inhibits plaque.

Prevention of erosive/abrasive enamel wear due to orange juice modified with dietary supplements

OBJECTIVE

The aim of this study was to evaluate the erosive/abrasive enamel wear after contact with orange juices modified with different dietary supplements.

METHODS

A total of 96 bovine enamel samples were prepared and allocated to eight groups (1-8; n = 12). Samples were eroded (120 s) in 200 ml of the following eight solutions: 1: water (control), 2: orange juice, 3: water + calcium effervescent tablet, 4: orange juice + calcium effervescent tablet, 5: water + 0.75 g acid/base regulating powder (Probase), 6: water + 0.375 g Probase, 7: orange juice + 0.75 g Probase and 8: orange juice + 0.375 g Probase. After erosion, the samples were brushed with 40 brushing strokes (load 2.5 N). Enamel wear was measured using surface profilometry after 20 and 40 cycles of erosion/abrasion respectively.

RESULTS

Highest mean enamel wear (± SD) after 20 and 40 cycles of erosion/abrasion was observed for the unmodified orange juice (group 2) (0.605 ± 0.240 μm; 1.375 ± 0.496 μm respectively). The enamel wear in all other groups (3-8) was significantly lower (P < 0.0001 respectively) with no significant difference within these groups and compared with water (control).

CONCLUSION

Erosive/abrasive enamel wear induces by orange juice and tooth brushing could be reduced significantly by modification with free available dietary supplements.

Effect of fluoride pretreatment on primary and permanent tooth surfaces by acid-etching

This study observed the effect of fluoride application on a 37% phosphoric acid etching for 20 s of the enamel surfaces of primary and permanent teeth based on a clinical protocol employed in dental hospitals, through atomic force microscopy and scanning electron microscopy. Enamel samples were prepared from 84 exfoliated and noncarious teeth. Primary (groups 1-4) and permanent (groups 5-8) tooth samples were assigned randomly to one of eight groups based on the timing of acid-etching with 37% phosphoric acid after an acidulated phosphate fluoride (APF) treatment. Groups 1 and 5 received no fluoride application. Groups 2-4 and 6-8 were pretreated with fluoride and received acid-etching 2 weeks later (groups 2 and 6), 1 week later (groups 3 and 7), and immediately (groups 4 and 8). The acid-etching process led to a significant increase in roughness (p<0.0001), and the APF treatment led to a decrease in primary and permanent tooth surface roughness (p<0.005). An acid-etching procedure 2 weeks after performing an APF pretreatment might be recommended to obtain the maximum enamel adhesion of a resin composite.

Effects of fluoride treatment on phosphoric acid-etching in primary teeth: an AFM observation

The aim of this study was to examine the effect of fluoride application on 37% phosphoric acid-etching by atomic force microscopy (AFM) in primary tooth samples based on a clinical protocol used in a pediatric dental hospital. Enamel samples were prepared from 36 exfoliated and non-carious primary teeth. Primary tooth samples were randomly assigned to one of the four groups based on the timing of acid-etching with 37% phosphoric acid after an acidulated phosphate fluoride (APF) pre-treatment. Group 1 received no fluoride application, Group 2 was pre-treated with fluoride and then received acid-etching 2 weeks later. One week separated the fluoride treatment and the acid-etching in Group 3, while Group 4 received acid-etching immediately after the fluoride treatment. The vestibular enamel surfaces of each primary tooth sample were scanned in air at a resolution of 512 x 512 pixels and a scan speed of 0.8 line/s. On the enamel surfaces of the primary teeth after APF pre-treatment, debris were observed although the teeth were smoother than they were prior to APF. As a result, it was concluded that APF treatment is responsible for decreased primary tooth surface roughness. The enamel surfaces etched for 20s showed that acid-etching was effective not only in removing scratches and debris, but also for evaluating enamel rod characteristics. Primary tooth enamel surfaces after etching showed minute structures caused by the decreased hydroxyapatite nanoparticle space, compared to those before etching. Also, acid-etching showed significantly increased roughness effects (p<0.0001, n=9). Finally, as more time elapsed after APF pre-treatment, the roughness was decreased to a lesser degree (p=0.005, n=9). We suggest that primary teeth etching 2 weeks after APF pre-treatment used clinically in pediatric hospitals may be effective to obtain properly etched enamel surfaces.